A concise copper catalysis strategy for the addition−cyclization of cyclic oxime esters across 1,6-enynes with high stereoselectivity to generate 1-indanones bearing an allcarbon quaternary center is reported. In this process, singleelectron reduction of cyclic oxime esters enables deconstructive carbon−carbon cleavage to provide a key cyanopropyl radical poised for the addition−cyclization. This reaction is redox-neutral, exhibits good functional group compatibility, and features 100% atomic utilization. This process driven by copper catalyst makes readily available cyclic oxime esters as bifunctional reagents to demonstrate convergent synthesis.
A new electrochemical selective annulative amino-ketalization and amino-oxygenation of 1,6-enynes with disulfonimides and alcohols is reported, producing a series of functionalized benzofurans under catalyst- and oxidant-free conditions. An annulative aminoketalization...
Manipulating active sites of catalysts is crucial but challenging in catalysis science and engineering. Beyond the design of the composition and structure of catalysts, the confined electromagnetic field in optical cavities has recently become a promising method for catalyzing chemical reactions via strong light−matter interactions. Another form of confined electromagnetic field, the charge density wave in plasmonic cavities, however, still needs to be explored for catalysis. Here, we present an unprecedented catalytic mode based on plasmonic cavities, called plasmonic cavity-catalysis. We achieve direct control of catalytic sites in plasmonic cavities through standing hot carrier waves. Periodic catalytic hotspots are formed because of localized energy and carrier distribution and can be well tuned by cavity geometry, charge density, and excitation angle. We also found that the catalytic activity of the cavity mode increases several orders of magnitude compared with conventional plasmonic catalysis. We ultimately demonstrate that the locally concentrated long-lived hot carriers in the standing wave mode underlie the formation of the catalytic hotspots. Plasmonic cavity-catalysis provides a new approach to manipulate the catalytic sites and rates and may expand the frontier of heterogeneous catalysis.
A metal‐free radical multicomponent bicyclization of heteroatom‐linked 1,7‐diynes with aryl diazonium tetrafluoroborates and DABCO‐bis(sulfurdioxide) (DABSO) is reported, enabling annulative SO2 insertion access to produce two types of skeletally diverse tricyclic sulfones, namely, thieno[3,4‐c]quinoline 2,2‐dioxides and thieno[3,4‐c]chromene 2,2‐dioxides, with moderate to good yields by simply tuning the linkers of the 1,7‐diynes. This protocol demonstrates remarkable compatibility regarding N‐ and O‐linked 1,7‐diynes with different substitution patterns and aryl diazonium tetrafluoroborates.
A palladium‐catalyzed intermolecular dearomative formal [4+2] annulation of phenols with propargyl electrophiles is reported, enabling substituent‐controlled regiodivergent synthesis of a wide range of skeletally diverse spirocyclohexadienones with good yields. The regiodivergence could be precisely controlled by adjusting the steric hindrance of O‐ and N‐substituents from binucleophilic substrates, where substrates with an O‐nucleophilic site were converted into spiro[chromane‐4,1′‐cyclohexane]‐2′,5′‐dien‐4′‐ones with complete regioselectivity and (Z)‐selectivity, whereas N‐nucleophiles enabled a different regiodivergent process to access spiro[cyclohexane‐1,4′‐quinoline]‐2,5‐dien‐4‐ones.
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